Conventionally, an air conditioning remote control system which performs pre-air conditioning for a passenger compartment of a vehicle by starting an air conditioning device of the vehicle using remote control before a ride is known.
For example, in a system disclosed in JP 2005-112129 A (Japanese Patent Application Laid-Open Publication), an operation order for an air conditioning device is transmitted from a mobile phone to an in-vehicle monitor device via a base station. When the in-vehicle monitor device receives the operation order, the monitor device determines whether an in-vehicle battery voltage is higher than a set voltage that enables an air conditioning device to operate/work, and it starts to operate the air conditioning device if the battery voltage is higher than the set voltage. Further, the in-vehicle monitor device notifies the mobile phone of whether or not the air conditioning device has started.